Isolation tools are used in oil and gas wells for running in or placement on tubing strings or casing strings for isolation of formations or pressures within the well. Isolation tools may include frangible disks, such as described in U.S. Pat. Nos. 9,291,031 and 5,924,696 and patent publication U.S. Pat. No. 2015/0068730, published Mar. 12, 2015, incorporated herein by reference.
One type of isolation tool has at least one frangible disk and is designed to be broken by dropping a weight or go-devil down the tubing or casing. Such a device is most typically used in vertical wells. However, sometimes isolation tools, such as isolation tools with a frangible disk(s) are intended for use in highly deviated or horizontal wells or wells with a horizontal leg. Such devices may use hydrostatic pressure to shear a disk responsive to a load on the disk, such as set forth in the '730 publication.